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How flexing of blood vessels during a heartbeat might contribute to heart disease

August 05, 2017

Patients entered the study between 1998 and 2001.  They had chest pain for 30 minutes in the past six to 12 hours and had evidence of acute myocardial infarction (heart attack) on their electrocardiograms.  Blood levels of ST2 were collected at baseline and at one, three, 12 and 24 hours after the heart attack.  Levels were then divided into four groups, or ???quartiles.???

Both increased heart rate and higher systolic blood pressure were associated with elevated ST2 levels, supporting the theory that ST2 is secreted by cardiac muscle cells under stress.

Researchers believe the protein receptor is induced in conditions of myocardial overload such as heart attack, when the remaining living heart muscle must work harder to make up for the dying tissue.  A similar overload occurs in the progression of heart failure, where ST2 levels are associated with the patient??ôs prognosis.

Heart muscle cells rapidly secrete one form of this protein when they become mechanically overloaded, Lee said.  ???When some heart muscle dies during the heart attack and the living heart muscle is stretched, the heart cells put out more ST2.???

An inflammatory response from damaged tissues may further stimulate the production of the protein in neighboring cells.

A blood test for ST2 may help predict the prognosis of patients after a heart attack, but measuring ST2 will not help in diagnosing heart attacks, the researchers said.  This is because not just heart muscle cells can secrete ST2.  For example, patients with asthma can also have increased levels of ST2 in their blood.

???We have a lot to learn, but we are excited about any new tool that could help in the prognosis of patients after a heart attack,??? Lee said.

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